Climate Engineering

Summary

Climate engineering, known as geoengineering, is a field of science that aims to deliberately control micro (local) and macro (global) climates by seeding clouds or shooting particles into the upper atmosphere to reflect the sun's rays. The goal is to reverse the effects of climate change.

Definition and Basic Principles

The term geoengineering comes from the Greek word geo, meaning "earth," and the word engineering, a field of applied science that incorporates and uses data from scientific, technical, and mathematical sources in the invention and execution of specific structures, apparatuses, and systems.

Not to be confused with geotechnical engineering, which is related to the engineering behavior of earth materials, geoengineering is a field of science that aims to manipulate both micro (local) and macro (global) climates to reverse the effects of climate change and global warming. Although geoengineering, or climate engineering, can be undertaken on the local level, such as cloud seeding, most proposed technologies are based on a worldwide scale for the wholesale mediation of the global climate and the effects of climate change.

Background and History

Human society and ancient cultures had long believed power over the weather to be the province of gods, but the advent of human-made climate control began with the concept of rainmaking (pluviculture) in the mid-nineteenth century. James Pollard Espy, an American meteorologist, was instrumental in developing the thermal theory of storms. Although such a discovery placed him in the annals of scientific history, he also became known (and disparaged) for his ideas regarding artificial rainmaking. According to Espy, burning huge forest areas would create sufficient hot air and updraft to create clouds and precipitation.

In 1946, Vincent Schaefer, a laboratory technician at General Electric Research Laboratory in New York, generated a cloud of ice from water droplets supercooled by dry ice. That same year, Bernard Vonnegut discovered that silver iodide smoke produced the same result. These processes came to be known as "cloud seeding." Cloud seeding attempts to encourage precipitation to fall in arid or drought-stricken agricultural areas by scattering silver iodide in rain clouds. Traditional climate modification has generally been limited to cloud seeding programs on a regional or local level.

In the following years, particularly during the Cold War, researchers in countries including the United States and the Soviet Union investigated climate control for its potential as a weapon. The Soviets also looked at climate control to warm the frozen Siberian tundra. However, in the 1970s, as concern regarding the greenhouse effect began to be expressed within conventional scientific circles, the concept of climate engineering took on new global significance.

Italian physicist Cesare Marchetti coined the term geoengineering in 1977. The word initially described the specific process of carbon dioxide capture and storage in the ocean depths as a means of climate change abatement. Since then, the term has been used to cover all engineering work performed to manipulate the global and local climate. In later years, many researchers have begun using the term climate engineering, a more accurate way to describe this type of applied science.

How It Works

Significant scientific evidence points to human activities, particularly the burning of fossil fuels, as playing a role in global climate change. An increase in the level of greenhouse gases, particularly carbon dioxide and methane, is a primary culprit. Scientists agree that the safest and best way to tackle climate change is to reduce fossil fuel consumption by implementing green technology, societal changes, and industry regulations. Although carbon reduction technology is available and relatively affordable, many scientists are increasingly concerned that carbon reduction schemes will not be introduced in time to stop the effects of climate change. As a result, interest in geoengineering technology to provide rapid solutions to climate change has increased.

There are two main areas of geoengineering research—carbon dioxide removal (CDR) and solar radiation management (SRM). Techniques based on CDR propose to remove carbon dioxide from the atmosphere and store it, while SRM techniques seek to reflect solar radiation from the Earth's atmosphere (or surface) back into space. Both techniques aim to combat climate change and reduce global temperatures but differ in implementations, time scales, temperature effects, and possible consequences. According to the Royal Society of London, CDR techniques “address the root cause of climate change by removing greenhouse gases from the atmosphere,” while SRM techniques “attempt to offset effects of increased greenhouse gas concentrations by causing the Earth to absorb less solar radiation.”

The CDR approach removes carbon dioxide from the atmosphere and sequesters it underground or in the ocean. Many consider this approach to be the more attractive of the two as it not only helps reduce global temperatures but also works to combat issues such as ocean acidification caused by escalating carbon dioxide levels. Conversely, SRM techniques do not affect atmospheric carbon dioxide levels, instead using reflected sunlight to reduce global temperatures.

Applications and Products

Traditionally, climate modification took the form of regional or local cloud seeding programs. In cloud seeding, a substance, usually silver iodide, is scattered in rain clouds to cause precipitation in arid or drought-stricken agricultural areas. By the start of the twenty-first century, however, deleterious global climate change and increasing atmospheric carbon dioxide levels had pushed climate engineering to the forefront of science. Geoengineering technology began being investigated as a possible weapon in the fight against climate change.

Geoengineering applications and products are generally regarded as highly speculative and environmentally untested, with significant ambiguity concerning global and institutional regulation. Although climate engineering theories abound, few have captured global attention for their feasibility and applicability.

Iron Fertilization of the Oceans. The intentional introduction of iron into the upper layers of certain ocean areas to encourage phytoplankton blooms is a form of CDR. The concept relies on increasing certain nutrients like iron in nutrient-poor areas stimulating phytoplankton growth. Carbon dioxide is absorbed from the ocean's surface during photosynthesis. When the phytoplankton, marine animals, and plankton die and sink in the natural cycle, that carbon is removed from the atmosphere and sequestered in the ocean's depths.

Scrubbers and Artificial Trees. Both scrubbers and artificial trees aim to remove and store carbon dioxide from the Earth's atmosphere and assist in reducing the effect of climate change. Scrubbing towers involves using large wind turbines funneling air into specially designed structures, where the air reacts with several chemicals to form water and carbonate precipitates, essentially capturing the carbon. These carbon precipitates can then be stored. Using artificial trees seeks the same result but by a different method. Large artificial trees or structures act as filters to capture and convert atmospheric carbon dioxide into carbonate, which is then removed and stored.

Biochar is a form of charcoal created from the pyrolysis (chemical decomposition by heating) of plant and animal waste. It captures and stores carbon by sequestering it in biomass. The biochar can be returned to the soil as fertilizer that helps the soil retain water, necessary nutrients, and carbon.

Stratospheric Sulfur Aerosols. Stratospheric sulfur aerosols are minute sulfur-rich particles found in the Earth's stratosphere often observed following significant volcanic activity (such as after the 1991 Mount Pinatubo eruption). The presence of these aerosols in the stratosphere results in a cooling effect. The SRM geoengineering technique of intentionally releasing sulfur aerosols into the stratosphere is based on the concept that they would produce a cooling or dimming effect by reflecting solar radiation. A workable delivery system has not yet been developed, but proposals include using high-altitude aircraft, balloons, and rockets.

Orbital Mirrors and Space Sunshades. The SRM technique of orbital mirrors and space sunshades entails the release of many billions (possibly trillions) of small reflective objects at a Lagrangian point in space to partially reflect solar radiation or impede it from entering the Earth's atmosphere. The theory is that decreasing sunlight hitting the Earth's surface would help decrease average global temperatures.

Marine Cloud Whitening. Marine cloud whitening involves increasing the reflective properties of cloud cover so that solar radiation entering the Earth's atmosphere is reflected back into space. Proposed methods for achieving this include mounting large-scale mist-producing structures on seafaring vessels. The theory is that the spray of minute water droplets released by these structures would increase cloud cover and whitening, increasing sunlight reflection. This method was tested in April 2024.

Reflective Roofs. Reflective or white roofs are often considered the most cost-effective and easily implemented SRM method of reducing global temperatures. The concept relies on reflecting solar radiation into space using white materials (or paint) on the surface of building roofs.

Careers and Course Work

Most commonly, students who wish to pursue careers in climate engineering begin by majoring in scientific fields such as atmospheric science, marine systems, and civil engineering. However, given the multitude of fields covered in geoengineering, a career in this applied science could follow many different paths, and students should have a solid understanding of atmospheric chemistry, ecology, meteorology, plant biology, ecosystem management, marine systems and chemistry, and engineering. Most graduate programs in this area are open to students with backgrounds in engineering, applied sciences, or closely related disciplines. University research covers many areas, and students who obtain a doctorate or master's degree in climate engineering can expect to have careers in geoengineering research and design, atmospheric sciences, aeronautical and nautical engineering, and environmental management consulting.

Social Context and Future Prospects

In the past, global geoengineering was regarded as more science fiction than fact. With greenhouse gas emissions continuing to increase from the burning of fossil fuel, however, the concept of deliberately engineering the Earth's climate is garnering interest and gaining credibility.

Engineering the climate could assist in lowering atmospheric carbon dioxide and reducing climate change impact. Although most geoengineering scientists stress that such technology should be used only for emergency quick fixes or as a last resort, many stress that research into such technology is imperative. The 2009 Royal Society report strongly advocated increased research and recommended the world's governments allocate some £100 million ($165 million), collectively, per year to examine geoengineering options. In the United States, the National Commission on Energy Policy conducted a study on geoengineering in 2011 and recommended increased research including establishing a substantial research program. In January 2020, the National Oceanic and Atmospheric Administration (NOAA) received $4 million from the US Congress to study two methods to cool the Earth—sulfur aerosols and sea salt aerosols. These methods were also researched and recommended in the 2020 report titled "Climate Intervention Strategies that Reflect Sunlight to Cool Earth" by the National Academies of Sciences, Engineering, and Medicine.

In April 2024, the New York Times reported that researchers at the University of Washington performed the nation’s first practical test of promising climate technologies. Researchers launched microscopic particles of salt into the atmosphere from the deck of a decommissioned aircraft carrier in San Francisco, California—the USS Hornet Flight Deck Coastal Atmospheric Aerosol Research and Engagement Facility. Scientists developed a tool called the Cloud Aerosol Research Instrument (CARI) that uses seawater to produce mists a few times a day. Because climate engineering and research in solar radiation modification remained controversial, the project was kept a secret until its launch.

Despite the move into more mainstream science, climate engineering is controversial, and many technological, social, ethical, legal, diplomatic, and safety challenges remain. Purposefully modifying the climate to correct climate change caused by humans has been labeled ironic and potentially catastrophic. Significant concern has been raised about encouraging geoengineering research and technology. For example, many conservation organizations are concerned that access to such technology lessens the resolve of governments and individuals to tackle climate change by reducing one's ecological footprint and fossil fuel consumption. Some scientists have called for bans on projects such as solar geoengineering, noting the potential for serious adverse consequences. Organizations such as the Carnegie Climate Geoengineering Governance Initiative (C2G) have worked to increase conversations between various parties regarding geoengineering’s scientific and ethical impacts.

Another potential problem with geoengineering technology is that it may ignite tensions between nations. The ethical ramifications of solar engineering are unclear, and significant confusion and uncertainty exist regarding who should implement and control the global thermostat. If a country implements technology to fix one area and inadvertently adversely alters the climatic patterns in another country, who pays for the mishap? The consequences of climate manipulation on a global scale will almost certainly be unequal across nations. Such concerns stress the importance of conducting further research and using caution regarding any technological advance in geoengineering.

Bibliography

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Flavelle, Christopher. "Warming Is Getting Worse. So They Just Tested a Way to Deflect the Sun." The New York Times, 2 Apr. 2024, www.nytimes.com/2024/04/02/climate/global-warming-clouds-solar-geoengineering.html. Accessed 16 Apr. 2024.

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